We have already witnessed this physical manifestation of deep psychological conflict
in the cabin of Walton's ship, when Victor is first recovering from exposure to the
arctic elements (I:L4:10). A grieving Victor gnashes his teeth at the mere thought
of the Creature in II:1:6. When we next observe the phenomenon, it will be the Creature
who gnashes his teeth in response to the frustration of all his hopes (III:3:13 and
note). The prototype for this act is the Satan of Paradise Lost: compare VI.340.